The answer is b, decrease the oxygen gas pressure
The nervous system, i could be wrong.
Answer: What is the defining characteristic of eukaryotic cells? Put these in your own words.
Eukaryotic cells are defined by the presence of a nucleus containing the DNA genome and bound by a nuclear membrane (or nuclear envelope) composed of two lipid bilayers that regulate transport of materials into and out of the nucleus through nuclear pores.
What types of organisms have eukaryotic cells?
There is a wide range of eukaryotic organisms, including all animals, plants, fungi, and protists, as well as most algae. Eukaryotes may be either single-celled or multicellular.
A cladogram (from Greek clados "branch" and gramma "character") is a diagram used in cladistics to show relations among organisms. ... These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it.